Stomach pain has dozens of possible causes, ranging from something as simple as eating too fast to conditions that need medical attention. The location of the pain, when it started, and what other symptoms come with it are the biggest clues to figuring out what’s going on. Most stomach pain is temporary and resolves on its own, but knowing the patterns can help you tell the difference between a bad meal and something more serious.
Where the Pain Is Matters
Your abdomen houses many organs packed closely together, and pain in different areas often points to different problems. Upper right pain, just below the ribs, is commonly linked to gallbladder issues, liver inflammation, or ulcers. Upper left pain may involve the stomach itself, the spleen, or the pancreas. Lower right pain is the classic location for appendicitis, though it sometimes starts as vague discomfort near the belly button before migrating. Lower left pain often signals problems with the lower colon, like diverticulitis or, in women, ovarian cysts.
Pain that’s hard to pin down to one spot is common too. Generalized aching or cramping across the whole abdomen often comes from gas, bloating, a stomach virus, or early stages of food poisoning. If the pain stays vague and mild, it’s less likely to indicate a specific organ problem. If it becomes sharp and settles into one area, that’s more useful information for figuring out the cause.
Food Poisoning and Stomach Bugs
Infections are one of the most common reasons for sudden stomach pain. The timeline from eating contaminated food to feeling sick varies enormously depending on the germ involved. Staph bacteria can cause nausea, vomiting, and cramps within 30 minutes to 8 hours of eating. Salmonella takes 6 hours to 6 days to produce symptoms. Norovirus, the most common cause of stomach bugs, typically hits 12 to 48 hours after exposure with diarrhea, vomiting, and stomach pain. Some organisms like Campylobacter take 2 to 5 days, and E. coli around 3 to 4 days.
If you’re trying to figure out what made you sick, think back not just to your last meal but to everything you ate over the past few days. Most food poisoning runs its course in 24 to 72 hours. Bloody diarrhea, a fever above 101.5°F, or symptoms lasting more than three days are signs you may need medical evaluation.
Food Intolerances
If your stomach hurts repeatedly after eating certain foods, an intolerance may be the cause. Lactose intolerance is among the most common: when your body doesn’t produce enough of the enzyme that breaks down the sugar in dairy, the undigested lactose reaches your colon, where bacteria ferment it. The result is bloating, gas, cramps, and diarrhea, typically starting 30 minutes to 2 hours after consuming dairy.
Celiac disease is different. It’s an autoimmune condition where eating gluten triggers your immune system to damage the lining of your small intestine. Unlike a simple intolerance that causes discomfort but no lasting harm, untreated celiac disease leads to ongoing inflammation, nutritional deficiencies, and poor growth in children. The symptoms can overlap with lactose intolerance (pain, bloating, diarrhea), which is why celiac disease is frequently missed or misdiagnosed.
IBS: When Pain Keeps Coming Back
Irritable bowel syndrome is one of the most common digestive conditions and a frequent explanation for chronic, recurring stomach pain. It’s classified as a syndrome, meaning it’s defined by a pattern of symptoms rather than visible damage to the gut. Colonoscopies and imaging in people with IBS look normal.
The hallmark pattern is abdominal pain or discomfort occurring at least 12 weeks out of the past year, along with changes in how often you have bowel movements or changes in stool consistency. Many people with IBS cycle between constipation and diarrhea. Bloating, gassiness, mucus in the stool, and the sensation of needing to go without being able to are all typical. Symptoms often first appear in late adolescence or early adulthood, frequently during periods of emotional stress.
IBS does not cause bleeding, weight loss, fever, or anemia. If you have those symptoms, the concern shifts to inflammatory bowel disease (Crohn’s disease or ulcerative colitis), which causes actual inflammation and visible damage to the intestinal wall and carries an increased risk of colon cancer. IBD can be confirmed through imaging and lab tests; IBS cannot.
Medications That Upset Your Stomach
Common over-the-counter pain relievers like ibuprofen, aspirin, and naproxen are the most frequent medication-related cause of stomach problems. These drugs work by blocking a chemical pathway that also helps protect the stomach lining. With regular use, they can erode that protective barrier and cause pain, ulcers, or even bleeding.
Antibiotics are another major culprit. They disrupt the balance of bacteria in your gut, which can cause diarrhea, cramping, and in some cases a more serious infection called C. difficile colitis. This is particularly associated with certain classes of antibiotics. Antidepressants and other medications with anticholinergic effects can relax the valve between your stomach and esophagus, causing acid reflux and heartburn, while also slowing the colon and leading to constipation. Opioid pain medications slow the entire digestive tract, which is why constipation is one of their most predictable side effects.
If your stomach pain started around the same time you began a new medication, that connection is worth exploring with your provider.
Causes That Aren’t Digestive
Not all stomach pain originates in the stomach or intestines. Kidney stones and kidney infections can produce intense pain that radiates into the abdomen, particularly in the flanks and lower quadrants. Urinary tract infections sometimes cause lower abdominal pain alongside the more familiar burning with urination. In women, ovarian cysts, ectopic pregnancies, and pelvic inflammatory disease can all present as stomach pain.
Less intuitively, pain from the chest can sometimes be felt in the upper abdomen. This is worth knowing because heart-related symptoms occasionally mimic stomach problems, particularly in women and older adults. If abdominal pain comes with shortness of breath or gets worse with physical activity, that combination warrants prompt attention.
Stomach Pain in Children
Kids complain of stomachaches frequently, and the causes are often different from those in adults. Constipation is the single most common reason, followed by stomach bugs and urinary tract infections. Functional abdominal pain, where the pain is real but no underlying disease is found, is also very common in school-age children. In infants, colic is a major source of apparent abdominal discomfort.
The more serious possibilities in children include appendicitis, which can be harder to diagnose in younger kids because they may not describe or localize their pain as clearly as adults. Rarer conditions like intussusception (where one segment of intestine slides into another) tend to cause sudden, severe episodes of pain in very young children.
When Stomach Pain Is an Emergency
Most stomach pain doesn’t require an emergency room visit, but certain patterns signal something potentially dangerous. Sudden, severe pain that doesn’t ease within 30 minutes is one clear red flag. Continuous severe pain accompanied by nonstop vomiting may indicate a serious or life-threatening condition.
Appendicitis typically produces severe pain in the lower right abdomen, often alongside loss of appetite, nausea, vomiting, or fever. Acute pancreatitis causes pain in the middle upper abdomen that may last for days, sometimes worsening after eating, along with nausea and a rapid pulse. An ectopic pregnancy produces severe abdominal pain with vaginal bleeding and is a medical emergency requiring immediate treatment.
How Doctors Figure Out the Cause
When stomach pain needs investigation beyond a physical exam and blood work, the type of imaging your doctor orders depends largely on where the pain is. Ultrasound is the preferred first step for right upper quadrant pain, since it’s especially good at evaluating the gallbladder and liver without radiation. CT scans are the go-to for pain in the lower right or lower left abdomen, where appendicitis and diverticulitis are top concerns. When the pain is spread across the whole abdomen and the cause isn’t clear from the exam and lab results, CT is generally the most informative option.
For women of reproductive age, pelvic ultrasound is recommended when a gynecologic cause is suspected or a pregnancy test is positive. During pregnancy, ultrasound and MRI are preferred over CT because they avoid radiation exposure.